1. Field of the Invention
The present invention relates to a motion detector, and more particularly, to a motion detecting apparatus and method which periodically controls power supplied to an inertia sensor to reduce power consumption.
2. Description of Related Art
A system for detecting motion of an object includes an inertia sensor. The inertia sensor includes an accelerometer, a gyro sensor, or a geomagnetic compass sensor.
The inertia sensor described above has been widely used in navigation control systems such as automobiles, trains, ships, airplanes, and the like, or in automatic control systems such as factory automation equipment and robots. Also, the inertia sensor is being used in portable systems such as pedometers, cellular phones, and the like. In this instance, the inertia sensor is used to detect a vibration, an external impact, the movement of an object and the like.
For example, an inertia sensor may output a certain acceleration value according to a user's motion and measure a number of steps the user takes as a function of a pedometer. Also, an inertia sensor may be used to determine whether a cellular phone is in a sleep mode or in an operation mode. When the motion of a cellular phone is less than a certain level, the cellular phone goes into a standby mode. Namely, the cellular phone operates in a sleep mode so as to avoid the use of unnecessary power.
An inertia sensor generally detects three-dimensional information associated with inertia by using a circuit. In this case, the circuit operates according to the principle of inertia, gyroscopic principle and the like. However, an inertia sensor is generally supplied with direct current power and operates. Accordingly, in this instance, the inertia sensor consumes a lot of power.